Weird possible steering issue

[ccondo]

I was doing some spirited driving on the street the other day in my 2017 M4 competition and while driving around a curve it felt like the steering has received additional input that I didn't give it.

It was very weird. I was taking a (slightly banked) left hand turn and in mid corner I felt it pull a little to the left. It was like I pinched the steering wheel for a second, but I didn't. It reminded me of my old Honda Prelude SH that would torque vector and you could tell when it turned on - like something was pulling you into the turn.

I later had this happen on the same day again. Am I just feeling the differential do something?

[MrSmartyPants]

The rear dif does perform some torque vectoring. Its more subtle than other cars ive driven (evo X) but def there. Only happens on throttle though. So yes, it could be the dif.

[ccondo]

I was surprised how UN-subtle it was. It took away a bit of my confidence in the car, as it wasn't what I told the car to do. Considering the gts diff upgrade right now. I wonder if it will help.

[stealth70mde]

Yes, mine does that too and in a similar road pattern as you that I take every day at highway speed. It's a slightly left banked turn that gradually start banking the other way towards the end...

What is even weirder is that the steering wheel will resist me when I want to start to turn the wheel back to center. I can reproduce this behavior every single time when taking that specific curve. I guess the systems get confused as how to behave with this weird change of banking direction.

It's worse then the temperature is colder so I think the nannies intervenes too much when the tires start losing grip plus the systems trying to figure out the bank angle change. It does it less with MDM and I didn't try yet with DSC off. I definitely should try now that I think of it.

[ccondo]

The nannies in this car are atrocious. Even in MDM traction control comes on for me during shifts in a straight line with nitto nt01s on 305s. I get it has more torque, but common. Also this is going to heat up brake pads etc.

[MrSmartyPants]

Get the M4 GTS coding for traction control, the rear dif and steering. For me, it made a huge difference in enjoying the car. Especially the TC and dif. Hit up Alex @ Alpine.

[stevehifi]

does the M4GTS coding get rid of the squirrely-ness in mid-corner? It always feel like the front and back of the car are doing two different things during transitions. I've had this problem on banked ramps at 80mph+...

[MrSmartyPants]

Originally Posted by stevehifi

does the M4GTS coding get rid of the squirrely-ness in mid-corner? It always feel like the front and back of the car are doing two different things during transitions. I've had this problem on banked ramps at 80mph+...

I haven't really experienced that. For me the cp EDC damper coding composed the chassis better than stock. Also think the chassis is well balanced, I turn in and it always has grip. Mostly neutral mid corner steady throttle or off throttle. Add throttle and the torque vectoring just aids the car on turning. It's wonderful. Not all that much unlike a real mech dif setup.

For high speed ramps no issues either. Just need very temperate throttle inputs.

[stealth70mde]

There is a similar discussion here:

http://f80.bimmerpost.com/forums/sho....php?t=1397653

[elmerzasty]

That pull you're describing comes from tire sidewall flex. Try upping the tire pressure, especially the front.

[Adam_IWC_M4]

My M4 comp has been having the occasional issue turning into right hand bends with entry speeds around 50-70kmh in a “45” indicated corner. When I begin to turn in the car it suddenly “straightens” slightly then gives me the input I want. Feels like the steering is ignoring the wheel input for a split second, I’ve had the car aligned by my local Porsche centre, that didn’t fix the issue fully, the left front was only out by 5-6mm. It feels more like some lane assist taking control of the steering. Only really happens on these particular “ radius” right hand turns.

[MR_X]

Originally Posted by MrSmartyPants

Get the M4 GTS coding for traction control, the rear dif and steering. For me, it made a huge difference in enjoying the car. Especially the TC and dif. Hit up Alex @ Alpine.

This

I did the Thor flash. Huge difference. It’s still does the vectoring but way more predictable and is able to be used toward your advantage. That was the second thing I noticed right away after the flash.

[sxychubles]

Originally Posted by stealth70mde

Yes, mine does that too and in a similar road pattern as you that I take every day at highway speed. It's a slightly left banked turn that gradually start banking the other way towards the end...

What is even weirder is that the steering wheel will resist me when I want to start to turn the wheel back to center. I can reproduce this behavior every single time when taking that specific curve. I guess the systems get confused as how to behave with this weird change of banking direction.

It's worse then the temperature is colder so I think the nannies intervenes too much when the tires start losing grip plus the systems trying to figure out the bank angle change. It does it less with MDM and I didn't try yet with DSC off. I definitely should try now that I think of it.

Did this ever get resolved? Picked up an F80 and i'm having a similar issue. The dealerships are all telling me that my lane assist is on or that they don't feel anything strange.

[stealth70mde]

Originally Posted by sxychubles

Did this ever get resolved? Picked up an F80 and i'm having a similar issue. The dealerships are all telling me that my lane assist is on or that they don't feel anything strange.

I don’t have the car anymore but no, it was never solved.

[sxychubles]

Originally Posted by stealth70mde

I don’t have the car anymore but no, it was never solved.

Thanks for getting back to me. Did you get try the GTS tune?

[stealth70mde]

Originally Posted by sxychubles

Thanks for getting back to me. Did you get try the GTS tune?

I didn’t keep the car long enough to try the GTS tune…